/Engine/Plugins/Runtime/Metasound/Source/MetasoundEngine/Public/MetasoundGeneratorHandle.h
Note: We don't allow direct assignment to the OnGeneratorsGraphChanged delegate because we need to know that someone actually wants this message so we can start actively listening for the corresponding audio render thread callback. So these next members are private and a "client" that wants to be notified of the graph change have to call public functions declared above to add themselves.
typedef TMulticastDelegate_NoParams< void > FOnSetGraphMulticast